Details

Autor(en) / Beteiligte

• Lee, David R.
• Cullen, Susan E.

Titel

Disulfide structure of murine Ia alloantigens

Ist Teil von

• Molecular immunology, 1983, Vol.20 (1), p.77-87

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

1983

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• The tryptic (T) and T insoluble chymotryptic (TIC) peptide maps from 35S-cysteine (Cys) labeled, disulfide-linked I-A k dimer were compared to those from 35S-Cys labeled I-A k a and β chains which were not covalently linked. These comparisons indicated that the α and β chains found in the covalent I-A k dimer were not a specialized subset of I-A α and β chains. Furthermore, these data, along with the knowledge that alkylation of spleen cells prior to and during detergent solubilization prevents the formation of disulfide-linked I-A k dimer, indicate that covalent dimer formation is an inefficient and artifactual process. Comparison of the T and TIC peptide maps of reduced and nonreduced 35S-Cys labeled I-A k α and β chains suggests that the I-A k α chain contains one intrachain disulfide bond, whereas the I-A k β chain contains two intrachain disulfide bonds. Examination of the T and TIC peptide maps of the reduced and nonreduced 35S-Cys labeled I-A k dimer identifies the Cys-containing peptides which are involved in the formation of the artifactual I-A k dimer interchain (α-β) disulfide bond. Comparison of 35S-Cys labeled I-A k and I-E k α and β chains by T and TIC peptide mapping reveals considerably more homology between the two α-chains and between the two β-chains than is observed using other 3H-amino acid precursors, thus indicating that the I-A k and I-E k alloantigens are homologous in their amino acid sequences adjacent to the Cys resides. The reasons for the inability to induce formation of interchain (α-β) disulfide bonds in I-E kmolecules are discussed.